/*
 * 猴子吃桃程序_扩展1（4分）
 */

#include <stdio.h>

int main() {
	setbuf(stdout, NULL);

	int days, peach_remain = 1;

	printf("Input days:\n");
	scanf("%d", &days);

	for (int i = 0; i < days - 1; ++i) {
		peach_remain = 2 * (peach_remain + 1);
	}

	printf("x=%d\n", peach_remain);

	return 0;
}
